Input devices designed to be used with computers and electronic typewriters were originally based upon the keyboard designs of mechanical typewriters. As such, the keys were placed directly in front of the computer, or electronic typewriter, on a substantially horizontal keyboard. A consequence of this design is that the operator is forced to place his/her hands, wrists and/or shoulders in an unnatural position in order to enter data into the computer or electronic typewriter. It has been discovered that several problems can be associated with the unnatural positions required to use conventional keyboards. One of these problems is carpal tunnel syndrome, or CTS. It is believed that CTS may be caused by the bunching of sheaths, which surround tendons in the hands, that occurs when the wrists are bent while using a conventional keyboard. This bunching, in turn, can affect the median nerve in the carpel tunnel and may lead to CTS. Generally, CTS is characterized by sharp pains in the wrist and fingers, and in extreme cases can be permanently debilitating.
While CTS is one type of repetitive stress injury, several other injuries can be caused by prolonged and repetitive use of conventional keyboards. For example, conventional keyboards require the operator's wrists and forearms to be in an unnatural position in order to adjust to the horizontal plane of the keyboard. This can lead to muscle and tendon strain in the operator's wrist and arms. Furthermore, the unnatural position associated with conventional keyboards can place the weight of the operator's arms on his/her shoulders, neck and back, which may lead to unnecessary stress on the shoulder, neck and back muscles.
Recent statistics indicate that CTS and other repetitive stress injuries are some of the fastest growing occupational injuries in the United States. Furthermore, it has been estimated that 50 percent of the work force could eventually suffer from CTS or other repetitive stress injuries. The costs to both employers and employees as a result of computer, and specifically keyboard, related repetitive stress injuries are expected to be significant. Thus, there is a need for input devices, and more specifically keyboards, that are designed to minimize repetitive stress injuries.
Currently, there are several types of ergonomically designed keyboards. See, for example, U.S. Pat. No. 5,137,384 to Spencer et al.; U.S. Pat. No. 5,426,449 to Danziger; and U.S. Pat. No. 6,132,118 to Grezeszak. These patents show alternate designs for keyboards that provide wrist support and/or a non-horizontal keyboard surface. However, none of the above-mentioned patents disclose a keyboard housing that both supports the operator's arms/wrists and can be adjusted and/or pivoted to conform to the particular contours of the operator's hands and arms. With the number of jobs that require extended periods of computer use, it would be desirable to provide an input device that could address the limitations of the above-mentioned patents.